With Gitlab Enterprise Edition Premium, you can create auditor users, who are given read-only access to all projects, groups, and other resources on the GitLab instance.

First and foremost, an auditor user can perform all the actions that a regular user can. In projects that the auditor user owns, or has been added to, they can be added to groups, mentioned in comments, or have issues assigned to them. The one exception is that auditor users cannot create projects or groups.

In addition, the auditor will be granted read-only access to all other projects/groups/etc. on the GitLab instance.

The auditor role is not a read-only version of the admin role. The auditor will not be able to access the project settings pages, or the Admin Area.